NBC chief Greenblatt enjoying his network’s ratings surge

“The assignment I was given when I came here was to try and revive a broadcast network,” he explained. “I’m happy if people watch our shows on mobile devices and iPads, as long as we get paid for them. The word ‘broadcast’ can certainly expand to all those other ways of watching. But right now, the most efficient way for us to get paid for our programming is over-the-air broadcast. So that’s our No. 1 goal: to try to get people to come watch on the air.”

The message seems to be sinking in. NBC may be moving beyond its status as an also-ran and as a punch line (routinely mocked even by its own shows, including seven seasons of “30 Rock”). Indeed, this fall NBC was the lone Big Four network seeing year-to-year gains, while the others suffered losses.

Is NBC’s revival necessarily at the expense of other networks? For Mr. Greenblatt, it’s tempting to see the TV world in ecological terms, where any network on the brink of extinction is a threat to the entire biosphere, and where any growth is good for all.